Penetration

[Justin Bieber]

A rather scientific sounding word (especially when used when casually reffering to sex), when really its all quite simple. One thing enters into another thing.

[Donald Trump]

Penetration is the medical term for the penis entering into the vagina. Its a good way term for talking about sex if one wants to seem mature. Even if youre a dirty little pervert, youll sound like sex is more than just an emotionless action caused by hormones if you call it penetration rather than fucking around, doing it, etc.

[Dave Paprocki]

In sex the disappearence of the penis into the vaginal cavity and the rupturing the hymen.

[Britney]

to poke someone in a bodily orifice

[Little_Girl]

-To expand ones sexual horizons
-Forceful insertion of a flashdrive that doesnt quite fit in the USB port.
-That moment when your key doesnt fit in the keyhole, because its the wrong key to begin with, so you shove that mother fucking bitch up in there.
-When you ram that big ass rhino horn into the tree. (Also see [gay penetration] )

[Jessica]

Sometimes in a homosexual relation ship the penis will penetrate the anus

[Julene]

1. A word used to describe sex [situation] .
   As in very [deep] into her.
2. Go through something. As in [getting shot] through.

[PussyCat]

The action or process of penetrating something.